Boolean; if true, then the serializer will sometimes quote literals with an apostrophe instead of double-quote marks. This is allowed by recent versions of the Turtle spec, but was disallowed by earlier specifications, and not widely supported yet. Defaults to false.

A hashref of prefix => URI pairs to define preferred QName prefixes. There is no guarantee that these will be honoured, but they usually will. RDF::Prefixes does a damn good job without any help, so this is generally pretty unnecessary.